Process for preparing β&#39; form of copper 8-hydroxyquinoline

ABSTRACT

A process for the preparation of the β&#39; form of the copper chelate of 8-hydroxyquinoline (copper oxinate), stabilized compositions containing said chelate, fungicidal compositions containing said chelate, and the methods for using said β&#39; form chelate or compositions for combatting fungi are disclosed.

This is a division of application Ser. No. 572,606 filed Jan. 20, 1984,now U.S. Pat. No. 4,517,362, which is a continuation of Ser. No.393,219, filed June 28, 1982, now abandoned.

SUMMARY OF THE INVENTION

The invention relates to a process for preparing the β' form of thecopper chelate of 8-hydroxyquinoline. The β' form is prepared byreacting a salt of 8-hydroxyquinoline with a copper (II) salt in waterto produce the β form of the chelate, treating the aqueous reactionmixture with base to adjust the pH to about 2-9, isolating the β formand then drying the β form at a temperature between 40°-220° C. to yieldthe β' form of the chelate.

This invention also relates to stabilized compositions containing the β'form of the copper chelate of 8-hydroxyquinoline, to fungicidalcompositions containing said β' form and to methods for the use of theβ' form in combatting fungi.

BACKGROUND OF THE INVENTION

It has been known that the chelate of copper (II) with8-hydroxyquinoline, hereinafter referred to as copper oxinate, possessesbiocidal properties and is useful as a fungicide in the treatment ofcereal seeds and is also suitable for protecting plants. The advantagesof copper oxinate include being non-irritating, possessing very lowtoxicity, almost zero volatility, high stability and can be preparedwithout any ecological problems.

The copper oxinate currently marketed possesses valuable activityagainst fusarium diseases, glume blotch and bunt; however, its activityagainst leaf stripe of barley is rather low. It is one of the objects ofthe present invention to find a compund possessing all the advantages ofcopper oxinate, but also possessing a broad activity spectrum with ahigh level of efficacy.

It has also been known that copper oxinate is a polymorphous compound,i.e. it has various crystalline forms, see Palenik, Acta. Cryst., 1964,17(6), 687-695 and Suito, et al., Kolloid-z.z. Polym., 1966, 212(2),155-161. Seven crystalline forms of copper oxinate have been reported,namely α, α', β, β', β", γ and γ' forms. The α, α', γ and γ' forms areconsidered as laboratory curiosities, while the β form is the moststable under normal conditions in which copper oxinate is used.

It has been found that the β' form of copper oxinate, considered to beunstable and to be a transition form between the β form, which is stableunder normal conditions, and the β" form, which is stable at highertemperatures, in fact possesses a broader activity spectrum than the βform and exhibits enhanced efficacy as an antifungal agent.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a process for preparation of the β'form of the copper chelate of 8-hydroxyquinoline (i.e. copper oxinate).The process of the present invention for preparing the β' form of copperoxinate comprises:

(a) reacting a salt of 8-hydroxyquinoline and a copper (II) salt inwater;

(b) adding a base until the pH of the reaction is between 2 and 9;

(c) recovering the precipitate of the β form of copper oxinate and

(d) drying the β form of copper oxinate at a temperature between about40° C. and about 220° C. to yield the β' form of copper oxinate.

Copper oxinate in the β' form has a molecular formula (C₉ H₆ ON)₂ Cu andis in the form of a strongly electrostatic, olive-green solid having afilamentous microstructure. The principal X-ray diffraction lines indecimal degrees are: (2θ)=7.15; 11.95; 13; 14.7.

In contrast to the vast majority of organic compounds which can beobtained as pure species by physical purification methods, thephysicochemical characteristics of oxine chelates (8-hydroxyquinolinechelates) and particularly the copper (II) oxine chelate are completelydetermined by the quality of each of the starting materials used, by thecomposition of the reactants, and by the conditions under which thereaction is carried out, including those relating to washing and drying.

In carrying out the process of this invention, step (a) is conducted inan aqueous phase, preferably an aqueous solution of an oxine salt (i.e.salt of 8-hydroxyquinoline) is reacted with an aqueous solution of acopper (II) salt. It is preferable to carry out this reaction utilizinga slight stoichiometric excess of the oxine salt, for example, less than5 mol percent.

The preferred oxine salt for this reaction is oxine sulfate; however,other acid addition salts of oxine can be utilized, for example, thenitrate and the phosphate.

The preferred copper (II) salt is copper (II) sulfate; however, othercopper (II) salts can be utilized, for example, the nitrate and thephosphate.

The reaction of the oxine salt and the copper (II) salt is carried outat a temperature below 40° C. and, preferably between 0° C. and 20° C.,for example, about 10° C.

The acidity resulting from the reaction in step (a) is neutralized insitu by addition of a base. The addition of base is carried out at thesame temperature as step (a). Examples of bases which can be employed inthe process include ammonia, alkali metal or alkaline earth metalhydroxides, or organic amines. The preferred base is ammonia.

The pH at the end of the reaction is critical because, by adjusting thelatter within the range of 2.0-3.5, preferably with the range 2.5-2.8,it is possible to free the reaction mixture not only for the oxineresulting from the neutralization of the excess 8-hydroxyquinoline salt,but also the major part of the oxinates of the other metals which areinevitably present in the reactants, for example Fe, Ni, Ca, and Mg.

The drying step (d) is carried out at temperatures between 40° and 220°C., and preferably between 60° and 160° C. In the latter temperaturerange, the time period for drying the product will vary between 0.5second to 120 minutes. If the drying temperature is in the range of 80°to 140° C., the time of drying will be from 0.5 second to 20 minutes. Itis understood that the higher the temperature, the shorter the dryingtime. It should be noted that if the β' form is kept at a hightemperature too long, it is converted to the β" form, which is furtherconverted to the stable β form at ambient temperatures. In fact, over aperiod of 275 hours at 30° C., 80% of the β" polymorph is converted tothe β form in the presence of water.

The copper oxinate in the β' form prepared according to the process ofthis invention contains less than 1% of impurities, which makes it aparticularly valuable product for the protection of plants.

As noted above, copper oxinate in the β' form is readily converted tothe β form in the presence of water. In the majority of applications,copper oxinate is used in an aqueous medium, for example, in the form ofconcentrated or dilute aqueous mixtures and, therefore, the use of theβ' form in such mixtures would lead to rapid conversion to the β form.

For practical use of copper oxinate in the β' form, it is, therefore,necessary to have available stabilized compositions, for example,wettable powders or aqueous suspensions, which can be stored withoutconversion to the β form and which can be diluted in water at least 24hours before use, without loss of activity of the product.

Another aspect of the present invention relates to stabilizedcompositions comprising copper oxinate in the β' form, as the activeingredient, and an agent for inhibiting the hydration of the copperoxinate in the β' form.

Examples of agents for inhibiting hydration of copper oxinate in the β'form include low molecular weight phenoplast-type polycondensates ofcresol and formaldehyde, polycondensates of alkylnaphthalenesulfonicacids with formaldehyde, commonly referred to aspolyalkylnaphthylmethanesulfonics, and their salts, arenesulfonic acids,for example, benzenesulfonic acid, toluenesulfonic acid,naphthalenesulfonic acid and their salts, polyacrylic acids, theirhomologoues and their salts, and lignosulfonic acid and lignosulfonates.In addition to their stabilizing properties, the foregoing materials aredispersing surfactants.

In addition to their inherent physicochemical properties, thestabilizers are characterized by the buffering capacity which theyimpart to the solution, and the presence in their molecules offunctional groups, especially OH and/or NH₂ and/or SO₃ H groups. Thesefunctional group are capable of forming a bond of low energy with thecopper atom. The following substances are particularly effectivehydration inhibitors: 8-hydroxyquinoline-5-sulfonic acid (sulphoxine)and its salts, and halogen substituted sulphoxines, preferably7-iodo-8-hydroxyquinoline-5-sulfonic acid and its salts.

Other materials which can be employed in the compositions of the presentinvention include polyvinyl alcohol, alkylcelluloses andhydroxyalkylcelluloses, carboxyalkylcelluloses, polyvinylpyrrolidone,polyacrylamides, carbohydrates, such as starches, hemicelluloses andgums, and polypeptides, in particular casein and caseinates, includingpowdered milk. These materials impart adhesion to spraying compositionsand also have a pronounced stabilizing action and partially inhibit thehydration of the β' form.

The concentration of stabilizer in the compositions of this inventiondepends on the nature of the stabilizer and also varies as a function ofthe nature of the composition. In general, the stabilizer will bepresent in the composition in the range of from about 0.1 percent byweight to about 20 percent by weight.

It should be pointed out that copper oxinate is both a brittle andfriable material. Therefore, in order to obtain uniform particles havinga size which is at the limit of detection of an optical microscope, i.e.in the region of 10⁻⁴ or 10⁻⁵ cm, it is necessary to employ percussionand attrition methods of fragmentation. To obtain the desired particlesize, any type of ultramicronization grinder, for example, jetmicronizers (air or steam jets) can be used. Preferably, ball grindersor bead mills operating along a horizontal or vertical axis areemployed. The procedure is carried out on an aqueous suspension havingan oxinate concentration between about 1 and 80% by weight, preferablybetween 20 and 50% by weight. A colloidal solution containing copperoxinate particles in the appropriate size range can be prepared usingbeads having a diameter of 1.5 mm as the grinding bodies. During thegrinding procedure, all the necessary adjuvants are added to impartstability to the allotrope in question, to assist the micronization orto impart, to the suspension, the optimum characteristics suited to thetype of application contemplated.

This invention is also directed to fungicidal compositions useful incombatting fungi of plants and especially seeds. The fungicidalcompositions comprise a compatible carrier material and, as the activeingredient, copper oxinate in the β' form. These compositions can be,for example, spray liquors, aqueous suspension, and emulsions. They maycontain from about 5-20% by weight β' copper oxinate and from about0.5-5% of hydration inhibitor, the rest to 100% being carrier material.

Examples of compatible carrier materials include pulverous materials,such as, for example, kaolin, chalk, bentonite, talc, whiting, magnesiumcarbonate and siliceous earth. The compositions may also contain wettingagents, inert diluents, solvents, dispersing agents and stabilizers.

Representative examples of the inventive fungicidal compositions are thefollowing:

Compositions for treating the aerial parts of plants, which can beapplied in the form of diluent aqueous sprays:

    ______________________________________                                        Ingredient                                                                    ______________________________________                                        I.                                                                            copper oxinate, β' form                                                                            50%                                                 sodium polynaphthylmethanesulfonate                                                                      2%                                                 sodium lignosulfonate      3%                                                 sulphoxine (8-hydroxyquinoline-5-sulfonic acid)                                                          1%                                                 chalk                     19%                                                 kaolin                    25%                                                 II.                                                                           copper oxinate, β' form                                                                            400    g                                            sodium polynaphthylmethanesulfonate                                                                     15     g                                            sodium lignosulfonate     25     g                                            sulphoxine                10     g                                            ethylene glycol           50     g                                            colloidal silica          25     g                                            silicone anti-foam agent  2      g                                            polysaccharide            2      g                                            water, q.s.p.             1      liter                                        ______________________________________                                    

The antifungal treatment of seeds may also be combined with protectionagainst insects of the soil as well as bird repellent agents. Lindane isan example of an insecticide which can be employed, and anthraquinone isan example of a bird repellant that may be employed.

An example of a triple composition for treating seeds which can be usedin the form of a concentrated aqueous spray is:

    ______________________________________                                        Ingredient                                                                    ______________________________________                                        copper oxinate, β' form                                                                         15%                                                    lindane                25%                                                    anthraquinone          25%                                                    sodium polynaphthylmethanesulfonate                                                                   1%                                                    sulphoxine             0.2%                                                   kaolin                 14.8%                                                  chalk                  10%                                                    polyvinyl alcohol       5%                                                    red 53-1*               4%                                                    ______________________________________                                         *[(4-Hydroxy-1-naphthalenyl)azo]-4'-chloro-5'-methyl-benzene-sulfonic         barium salt.                                                             

The copper oxinate in the β' form can also be used in the protection ofanimal feeds and leather, in the protection of cellulose materials, suchas paper pulp, wood, paint, glue and fabrics, and also for theprotection of hydrocarbons.

The following Examples illustrate the present invention.

EXAMPLE 1 Preparation of the β polymorph: (C₉ H₆ ON)₂ Cu.2(OH₂)

A solution prepared from 232.11 g (0.5688 mol and +0.5%) of oxinesulfate and 1,000 ml of water is added, over a period of 30 minutes andwith vigorous stirring, to a solution, kept at 10° C., consisting of 142g (0.5688 mol) of copper sulfate pentahydrate and 1,200 ml of water. Thecopper oxinate, which has a delicate green color, appears from theintroduction of the first drop of reactant, and the polymorphicconversion α→γ→β can be followed by examination under a microscope.

The reactants mix without heating being evolved. While maintaining theinitial temperature, 85% of the theoretical amount of ammonia (170 ml,d_(20/4) =0.924) is introduced dropwise and then, following the pH, theneutralization is continued until the pH is between 2.5 and 2.8(≃10 ml).The temperature is allowed to rise until it reaches ambient temperature,with gentle stirring. The chelate, which is in the form of hexagonal 20μlamellae, is filtered off, washed with water (350 ml), drained and leftto dry in the open air or using a suitably adjusted fluidized bedapparatus. This yields 250 g of moist product and 219.12 g (yield:99.4%) of dry product having the following characteristics:

% of (C₉ H₆ ON)₂ Cu=90.45; % of H₂ O=9.45; total content of impurities(other metal oxinates, ammonium sulfate, oxine and water): ≦0.40%;polymorphic purity by X-ray diffraction: 100%; position of the principalX-ray diffraction lines and in decimal degrees: (2θ)=6.95; 15.75; 16.00.

Before being discarded, the mixture of the mother liquors and the washliquors (3 liters) is neutralized to pH 7-8 (≃50 ml) and then allowed tostand for 12 hours. The precipitate, which consists mainly of ironoxinate, that is to say about 0.450 g, cannot easily be removed byfiltration, but is more conveniently removed by centrifugation.

EXAMPLE 2 Preparation of the β' polymorph: (C₉ H₆ ON)₂ Cu

The process of drying the moist β polymorph of copper oxinate involvesthe following two successive steps:

(I) moist β-oxinate→β-oxinate+moisture;

(II) β-oxinate→β'-oxinate+2(OH₂).

The drying operation (I) can be carried out in the open air or by meansof a fluidized bed dryer. In a fluidized bed dryer, the air inlettemperature of which is adjusted to 40° C., the moisture is completelyremoved in 10 minutes, whereas the degree of conversion in the secondstep is imperceptible. In fact, to take place in the reasonable periodof 10 minutes, the latter requires a temperature of 85° C.

The process can also be carried out by continuously spraying the drycopper oxinate in the β form into a steam of hot air, the oxinate beingheated to a temperature of 135°-145° C. for a period of the order of asecond.

As regards the polymorphic purity, the results commonly obtained are: β:undetectable; β": ⊖1%. The strongly electrostatic, olive-green solid hasa filamentous microstructure under a scanning electron microscope.

Position of the principal X-ray diffraction lines in decimal degrees:(2θ)=7.15; 11.95; 13; 14.7.

EXAMPLE 3

The Example demonstrates the influence of a stabilizer on thepreservation of copper oxinate in the β' form at ambient temperature andat 60° C. The following compositions were prepared and used in the formof aqueous suspensions containing 5% by weight of copper oxinate in theβ' form.

Composition A

Copper oxinate in the β' form, containing 1% by weight of sulphoxine(8-hydroxyquinoline-5-sulfonic acid in the free form or in the form ofthe Na salt).

Composition B

Copper oxinate in the β' form, containing 10% by weight of Nalignosulfonate.

Composition C

Copper oxinate in the β' form, containing 5% by weight of polyoxyetherof tridecyl alcohol (unstabilized composition).

    __________________________________________________________________________              Percentage conversion to the β form                                                             Percentage conversion to the                           at ambient temperature β form at 60° C.                           0 h  2 h           6                                                Time      15 m                                                                             1 h                                                                             30 m                                                                             7 h                                                                             20 h                                                                             90 h                                                                             190 h                                                                            months                                                                            0 h 15 m                                                                           1 h                                                                              2 h 30                                                                            7 h                              __________________________________________________________________________    Aqueous suspension                                                                      4  22                                                                              52   92 100       0    100                                     containing 5% of                                                              copper oxinate in                                                             the β' form                                                              Composition A                                                                           0               0      0    0      0                                Composition B                                                                           0                  0                                                Composition C  92                                                             __________________________________________________________________________

These results indicate that the addition of a stabilizer considerablyincreases the ability of preserving copper oxinate in the β' form, inaqueous suspension, whereas the addition of a conventional wetting agentconsiderably accelerates the conversion to the β form.

The following Examples compare the activity of copper oxinate in the βand β' form in the protection of seeds. The test procedures employed arein accordance with those prescribed by the Commission des EssaisBiologiques de la Societe Francaise de Phytiatrie et de Phytopharmacie.

EXAMPLE 4

This Example compares the activity of the β and β' polymorphs againstsnow mould, glume blotch and bunt.

The following compositions were prepared:

    ______________________________________                                                          Percentage by weight                                        ______________________________________                                        Composition D                                                                 Copper oxinate, β form                                                                       16.60                                                     Polyethoxy ether of tridecyl alcohol                                                               0.75                                                     Chalk               29.20                                                     Kaolin              53.45                                                     Composition E                                                                 Copper oxinate, β' form                                                                      15.00                                                     Polyethoxy ether of tridecyl alcohol                                                               0.75                                                     Chalk               29.20                                                     Kaolin              55.05                                                     ______________________________________                                    

The compositions were used at a dose equivalent to 30 g/quintal ofcopper oxinate, expressed as (C₉ H₆ NO)₂ Cu. The seeds were treatedimmediately after preparation of the spraying composition.

The results observed in the protection of the seeds against thesediseases are reported in Table I.

                  TABLE I                                                         ______________________________________                                        ACTIVITY OF β AND β' COPPER OXINATE ON                              SNOW MOULD, GLUME BLOTCH AND BUNT                                             Percentage of healthy plantlets                                                          Nature of                                                                     the experiment                                                                SEED CUPS     OPEN                                                            Snow.sup.(1)                                                                           Glume.sup.(2)                                                                          FIELD                                                       mould    blotch   Bunt.sup.(3)                                     Disease      Day of counting                                                  Composition  S + 53     S + 83   Harvesting                                   ______________________________________                                        Composition D                                                                              74         25       92.8                                         Composition E                                                                              85         68.5     97                                           Untreated control                                                                          48          6       49.3                                         ______________________________________                                         .sup.(1) Rye contaminated to the extent of 32% by Fusarium                    .sup.(2) Clement wheat contaminated to the extent of 81% by Septoria          nordorum-                                                                     .sup.(3) Clement wheat artificially contaminated to the extent of             3.permill. by bunt                                                       

The activity of β' form is much greater than that of the β form.

EXAMPLE 5

This Example illustrates the effect of a stabilizer on the activity ofthe β and β' polymorphs of copper oxinate against snow mould, glumeblotch, bunt and leaf stripe of barley after 24 hours and in thepresence of water.

The following compositions were prepared:

Composition G

Copper oxinate, β form, at a concentration of 5.55% by weight/volume inwater.

Composition H

Copper oxinate, β' form, at a concentration of 5% by weight/volume inwater.

    ______________________________________                                        Composition I                                                                 ______________________________________                                        Copper oxinate, β' form                                                                         5      g                                               Na--lignosulfonate     0.5    g                                               Water, q.s.p.          100    ml                                              ______________________________________                                    

The compositions were used at a dose equivalent to 30 g/quintal ofcopper oxinate, expressed as (C₉ H₆ NO)₂ Cu. Unless indicated otherwise,the treatment of the seeds immediately followed the preparation of thespraying mixture. The results observed in the protection of the seedsagainst these diseases are reported in Table II.

                  TABLE II                                                        ______________________________________                                        EFFECT OF STABILIZER ON THE ACTIVITY                                          OF β AND β' COPPER OXINATE AGAINST SNOW                             MOULD, GLUME BLOTCH, BUNT AND LEAF STRIPE                                     Percentage of healthy plantlets                                                           Nature of                                                                     the experiment                                                                           OPEN                                                               SEED CUPS  FIELD                                                              Snow.sup.(1)                                                                        Glume.sup.(2)      Leaf.sup.(4)                                         Mould Blotch   Bunt.sup.(3)                                                                            Stripe                                   Disease       Day of counting                                                 Composition   S + 23  S + 55   Harvesting                                                                            Earing                                 ______________________________________                                        Composition G 69.3    14.7     94.9    80.4                                   Composition H 82      81.3     99.6    97.8                                   Composition H after 24 h                                                                    75.3    40       --      --                                     Composition I 80      78.3     98.9    98.8                                   Composition I after 24 h                                                                    82.7    76.7     99.6    99.1                                   Untreated control                                                                           63.3     5.3     80.6    63.6                                   ______________________________________                                         .sup.(1) Rye contaminated to the extent of 26% by Fusarium                    .sup.(2) Talent wheat contaminated to the extent of 75% by Septoria           nordorum-                                                                     .sup.(3) Clement wheat artificially contaminated to the extent of             3.permill. by bunt                                                            .sup.(4) Astrix winter barley contaminated to the extent of 56% by            Helminthosporium gramineum                                               

It is clearly apparent from Table II that the unstabilized aqueouscompositions containing copper oxinate in the β' form lose a large partof their activity after 24 hours, whereas the stabilized compositionsretain a virtually unchanged activity.

EXAMPLE 6

This Example illustrates the efficacy of copper oxinate in the β' formin the presence or absence of a stabilizer and in formulationscontaining other ingredients.

The following compositions were prepared:

    ______________________________________                                                            Percentage by weight                                      ______________________________________                                        Composition D                                                                 Copper oxinate, β form                                                                         16.60                                                   Polyethoxy ether of tridecyl alcohol                                                                 0.75                                                   Chalk                 29.20                                                   Kaolin                53.45                                                   Composition E                                                                 Copper oxinate, β' form                                                                        15.00                                                   Polyethoxy of tridecyl alcohol                                                                       0.75                                                   Chalk                 29.20                                                   Kaolin                55.05                                                   Composition J                                                                 Copper oxinate, β' form                                                                        15.00                                                   Sodium polynaphthylmethanesulfonate                                                                  1.00                                                   Sulphoxine            0.2                                                     Chalk                 29.2                                                    Kaolin                54.6                                                    ______________________________________                                    

The compositions were used at a dose equivalent to 30 g/quintal ofcopper oxinate, expressed as (C₉ H₆ NO)₂ Cu. Unless indicated otherwise,the treatment of the seeds immediately followed the preparation of thespraying mixture.

The results observed in the protection of the seeds against leaf spotare reported in Table III.

                  TABLE III                                                       ______________________________________                                        EFFECT OF STABILIZER ON THE ACTIVITY OF β AND                            β' FORM OF COPPER OXINATE ON GLUME BLOTCH                                Percentage of healthy plantlets                                               NATURE OF EXPERIMENT                                                          Disease              DISHES                                                   Composition          Leaf spot.sup.(1)                                        ______________________________________                                        Composition D        69.8                                                     Composition E after 24 hours                                                                       65.3                                                     Composition J after 24 hours                                                                       91.6                                                     Untreated control     9.8                                                     ______________________________________                                         .sup.(1) Talent wheat contaminated to the extent of 90% by Septoria           nodorum                                                                  

The results of Table III confirm the efficacy of the stabilizer asregards the β' polymorph.

EXAMPLE 7

This Example illustrates the efficacy of copper oxinate in the β' formin formulations containing other active ingredients, for example,insecticides and bird repellants.

The following compositions were prepared:

    ______________________________________                                                              Grams/liter                                             ______________________________________                                        Composition K                                                                 Copper oxinate, β form                                                                           133.3                                                 Lindane                 200                                                   Anthraquinone           200                                                   Polyethoxy ether of tridecyl alcohol                                                                  10                                                    Polyethoxy ether of nonylphenol                                                                       15                                                    Red 53-1*               35                                                    Ethylene glycol         50                                                    Water, q.s.p. to        1      liter                                          Composition L                                                                 Copper oxinate, β' form                                                                          120                                                   Lindane                 200                                                   Anthraquinone           200                                                   Red 53-1*               35                                                    Sulphoxine              10                                                    Sodium polynaphthylmethanesulfonate                                                                   20                                                    Polyvinyl alcohol       50                                                    Ethylene glycol         50                                                    Water, q.s.p. to        1      liter                                          ______________________________________                                         *[(4-Hydroxy-1-naphthalenyl)azo]-4'-chloro-5'methyl-benzene-sulfonic acid     barium salt.                                                             

The compositions were used at a dose equivalent to 30 g/quintal ofcopper oxinate, expressed as (C₉ H₆ NO)₂ Cu. Unless indicated otherwise,the seeds were treated immediately following preparation of the spraymixture.

The results observed in the protection of the seeds against glume blotchare reported in Table IV.

                  TABLE IV                                                        ______________________________________                                        EFFECT OF A STABILIZER ON THE ACTIVITY OF                                     β AND β' FORMS OF COPPER OXINATE                                    ON GLUME BLOTCH IN FORMULATIONS                                               CONTAINING OTHER ACTIVE INGREDIENTS                                           Percentage of healthy plantlets                                               NATURE OF EXPERIMENT                                                          Disease              SEED CUPS                                                Composition          Glume Blotch.sup.(1)                                     ______________________________________                                        Composition K        40.4                                                     Composition L after 24 hours                                                                       81.2                                                     Untreated control     9.5                                                     ______________________________________                                         .sup.(1) Talent wheat contaminated to the extent of 90% by Septoria           nodorum                                                                  

The results of Table IV confirm the efficacy of the stabilizer asregards the β' polymorph in formulations containing other activeingredients.

We claim:
 1. A stabilized composition comprising β' form of copper8-hydroxyquinoline and a hydration initiator selected from the groupconsisting of 8-hydroxyquinoline-5-sulfonic acid and salts thereof,halosub-stituted 8-hydroxyquinoline-5-sulfonic acid and salts thereof,and of 7-iodo-8-hydroxyquinoline-5-sulfonic acid and its salts.
 2. Afungicidal composition which comprises an effective amount of β' form ofcopper 8-hydroxyquinoline and a hydration inhibitor is selected from thegroup consisting of 8-hydroxyquinoline-5-sulfonic acid and saltsthereof, halosubstituted 8-hydroxyquinoline-5-sulfonic acid and saltsthereof, and of 7-iodo-8-hydroxyquinoline-5-sulfonic acid as its saltsand an inert carrier material.
 3. A method of controlling fungi onplants and seeds comprising treating said plants or seeds with afungicidally effective amount of the composition of claim
 2. 4. Thecomposition of claim 2 comprising from about 5-20% by weight of the β'copper-8-hydroxyquinoline, 0.5-5% by weight of the hydration inhibitorand the rest being carrier material.
 5. A stabilized compositioncomprising β' form of copper 8-hydroxyquinoline and a hydrationinhibitor selected from the group consisting of lignosulfonic acid andlignosulfates.
 6. The composition of claim 5 wherein the hydrationinhibitor is from 0.1 to 20 percent by weight.
 7. A fungicidalcomposition which comprises an effective amount of β' form of copper8-hydroxyquinoline, a hydration inhibitor selected from the groupconsisting of lignosulfonic acid and lignosulfonatesfand an inertcarrier material.
 8. The fungicidal composition of claim 7 comprisingfrom about 5-20% by weight of the β' copper-8-hydroxyquinoline, 0.5-5%by weight of the hydration inhibitor and the rest being carriermaterial.
 9. The composition of claim 1 wherein the hydration inhibitoris from 0.1 to 20 percent by weight.